Therapeutic Efficacy Evaluation of Pegylated Liposome Encapsulated With Vinorelbine Plus 111In Repeated Treatments in Human Colorectal Carcinoma With Multimodalities of Molecular Imaging.

BACKGROUND/AIM: In precision therapy, liposomal encapsulated chemotherapeutic drugs have been developed to treat cancers by achieving higher drug accumulation in the tumor compared to normal tissues/organs. MATERIALS AND METHODS: We developed a novel chemoradiotherapeutic approach via nanoliposomes conjugated with vinorelbine (VNB) and 111In (111In-VNB-liposome) and examined their pharmacokinetics, biodistribution, maximum tolerance dose, and toxicity in a NOD/SCID mouse model. RESULTS: Pharmacokinetic results showed that the area under the curve (AUC) of PEGylated liposomes was about 17-fold higher than that of the free radioisotope. Tumor growth inhibition by 111In-VNB-liposome was significantly higher than that of the control (p<0.05). CONCLUSION: The tumors in NOD/SCID mice bearing HT-29/tk-luc xenografts were significantly suppressed by 111In-VNB-liposomes. The study proposed repeated treatments with a novel liposome-mediated radiochemotherapy and validation of therapeutic efficacy via imaging.

Improvement of biodistribution and therapeutic index via increase of polyethylene glycol on drug-carrying liposomes in an HT-29/luc xenografted mouse model.

Liposomes modified with a high concentration of polyethylene glycol (PEG) could significantly prolong the retention time of the carried drug in the circulation, thus improving the drug accumulation in the tumor. In this study, 6 mol% rather than 0.9 mol% PEGylated liposomes (100 nm in diameter) encapsulated with indium-111 were used in a human colorectal carcinoma HT-29/luc tumor-bearing mouse model for comparing the PEGylation effect. Pharmacokinetics, biodistribution, passive-targeted assay, bioluminescence imaging (BLI) and tumor growth measurements were used for the spatial and temporal distribution, tumor localization and therapeutic evaluation of the drug. Pharmacokinetic studies indicated that the terminal half-life (T((1/2))lambdaz) and C(max) of 6 mol% PEG (111)In liposomes were similar to those of 0.9 mol% PEG (111)In liposomes. In the blood, the total body clearance (Cl) of 6 mol% PEG (111)In liposomes was about 1.7-fold lower and the area under the curve (AUC) was 1.7-fold higher than those of 0.9 mol% PEG (111)In liposomes. These results showed that the long-term circulation and localization of 6 mol% PEGylated liposomes was more appropriate for use in the tumor-bearing animal model. In addition, the biodistribution of 6 mol% PEG (111)In liposomes showed significantly lower uptake in the liver, spleen, kidneys, small intestine and bone marrow than those of 0.9 mol% PEG (111)In liposomes. The clearance rate of both drugs from the blood decreased with time, with the maximum at 24 h post intravenous (i.v.) injection. Prominent tumor uptake and the highest tumor/muscle ratios were found at 48 h post injection. Both AUC and relative ratio of the AUCs (RR-AUC) also showed that 6 mol% PEGylated liposomes significantly reduced the uptake of drugs in the reticuloendothelial system (RES), yet enhanced the uptake in the tumor. Gamma scintigraphy at 48 h post injection also demonstrated more distinct tumor uptake with 6 mol% PEG (111)In liposomes as compared to that of 0.9 mol% PEGylated liposomes (p<0.01). BLI and in vivo tumor growth tracing showed that growth in tumor volume could largely be inhibited by 6 mol% PEG (111)In liposomes. The results suggest that 6 mol% PEGylated liposomes might be a more suitable liposomal carrier for drug delivery than 0.9 mol% PEGylated liposomes, not only by reducing the drug accumulation in the RES or its related organs, but by prolonging drug circulation and eventually enhancing the targeting efficiency in the tumor to reach a better therapeutic index.

Diagnostic and therapeutic evaluation of 111In-vinorelbine-liposomes in a human colorectal carcinoma HT-29/luc-bearing animal model.

Colorectal carcinoma is a highly prevalent and common cause of cancer in Taiwan. There is still no available cure for this malignant disease. To address this issue, we applied the multimodality of molecular imaging to explore the efficacy of diagnostic and therapeutic nanoradiopharmaceuticals in an animal model of human colorectal adenocarcinoma [colorectal cancer (CRC)] that stably expresses luciferase (luc) as a reporter. In this study, an in vivo therapeutic efficacy evaluation of dual-nanoliposome (100 nm in diameter) encaged vinorelbine (VNB) and (111)In-oxine on HT-29/luc mouse xenografts was carried out. HT-29/luc tumor cells were transplanted subcutaneously into male SCID mice. Multimodality of molecular imaging approaches including bioluminescence imaging (BLI), gamma scintigraphy, whole-body autoradiography (WBAR) and in vivo tumor growth tracing, histopathology and biochemistry/hematology analyses were applied on xenografted SCID mice to study the treatments with 6% polyethylene glycol (PEG) of (111)In-NanoX/VNB-liposomes. In vivo tumor growth tracing and BLI showed that tumor volume could be completely inhibited by the combination therapy with (111)In-VNB-liposomes and by chemotherapy with NanoX/VNB-liposomes (i.e., without Indium-111) (P<.01). The nuclear medicine images of gamma scintigraphy and WBAR also revealed the conspicuous inhibition of tumor growth by the combination therapy with (111)In-VNB-liposomes. Animal body weights, histopathology and biochemistry/hematology analyses were used to confirm the safety and feasibility of radiopharmaceuticals. A synergistic therapeutic effect on CRC xenografted SCID mice was proven by combining an Auger electron-emitting radioisotope (Indium-111) with an anticancer drug (VNB). This study further demonstrates the beneficial potential applications of multimodality molecular imaging as part of the diagnostic and therapeutic approaches available for the evaluation of new drugs and other strategic approaches to disease treatment.

Cytotoxic Effects of PEGylated Anti-EGFR Immunoliposomes Combined with Doxorubicin and Rhenium-188 Against Cancer Cells.

BACKGROUND/AIM: We aimed to construct epidermal growth factor receptor (EGFR)-targeting cetuximab-immunoliposomes (IL-C225) for targeted delivery of doxorubicin and rhenium-188 (Re-188) to EGFR(+) cancer cells. MATERIALS AND METHODS: Synthesized IL-C225 was analyzed by dynamic light scattering, transmission electron microscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. Cell binding and internalization were examined using doxorubicin-loaded IL-C225 (DXR-IL-C225) with confocal microscopy. IL-C225 combined with doxorubicin and Re-188 ((188)Re-DXR-IL-C225) was synthesized, and the cytotoxic effects of (188)Re-DXR-IL-C225 were analyzed in EGFR(+) cancer cells using cell viability assays. RESULTS: IL-C225 bound to EGFR on A431 cancer cells and was rapidly internalized. Furthermore, IL-C225 localized within the tumor cells efficiently. (188)Re-DXR-IL-C225 exhibited outstanding cytotoxic effects against EGFR(+) cancer cells in vitro and showed superior cytotoxic effects compared to DXR-IL-C225 or (188)Re-IL-C225 alone. CONCLUSION: The new formulation of (188)Re-DXR-IL-C225 may be a potential theranostic vehicle for delivery of drugs in the treatment of EGFR-overexpressing human cancer.

Synergistic Effect of Sorafenib and Radiation on Human Oral Carcinoma in vivo.

Oral squamous cell carcinoma often causes bone invasion resulting in poor prognosis and affects the quality of life for patients. Herein, we combined radiation with sorafenib, to evaluate the combination effect on tumor progression and bone erosion in an in situ human OSCC-bearing mouse model. Treatment procedure were arranged as following groups: (a) normal (no tumor); (b) control (with tumor); (c) sorafenib (10 mg/kg/day); (d) radiation (single dose of 6 Gy); (e) pretreatment (sorafenib treatment for 3 days prior to radiation), and (f) concurrent treatment (sorafenib and radiation on the same day). The inhibition of tumor growth and expression level of p65 of NF-κB in tumor tissues were the most significant in the pretreatment group. EMSA and Western blot showed that DNA/NF-κB activity and the expressions of NF-κB-associated proteins were down-regulated. Notably, little to no damage in mandibles and zygomas of mice treated with combination of sorafenib and radiation was found by micro-CT imaging. In conclusion, sorafenib combined with radiation suppresses radiation-induced NF-κB activity and its downstream proteins, which contribute to radioresistance and tumorigenesis. Additionally, bone destruction is also diminished, suggesting that combination treatment could be a potential strategy against human OSCC.

Tumor burden talks in cancer treatment with PEGylated liposomal drugs.

PURPOSE: PEGylated liposomes are important drug carriers that can passively target tumor by enhanced permeability and retention (EPR) effect in neoplasm lesions. This study demonstrated that tumor burden determines the tumor uptake, and also the tumor response, in cancer treatment with PEGylated liposomal drugs in a C26/tk-luc colon carcinoma-bearing mouse model. METHODS: Empty PEGylated liposomes (NanoX) and those encapsulated with VNB (NanoVNB) were labeled with In-111 to obtain InNanoX and InVNBL in high labeling yield and radiochemical purity (all >90%). BALB/c mice bearing either small (58.4±8.0 mm(3)) or large (102.4±22.0 mm(3)) C26/tk-luc tumors in the right dorsal flank were intravenously administered with NanoVNB, InNanoX, InVNBL, or NanoX as a control, every 7 days for 3 times. The therapeutic efficacy was evaluated by body weight loss, tumor growth inhibition (using calipers and bioluminescence imaging) and survival fraction. The scintigraphic imaging of tumor mouse was performed during and after treatment. RESULTS: The biodistribution study of InVNBL revealed a clear inverse correlation (r (2) = 0.9336) between the tumor uptake and the tumor mass ranged from 27.6 to 623.9 mg. All three liposomal drugs showed better therapeutic efficacy in small-tumor mice than in large-tumor mice. Tumor-bearing mice treated with InVNBL (a combination drug) showed the highest tumor growth inhibition rate and survival fraction compared to those treated with NanoVNB (chemodrug only) and InNanoX (radionuclide only). Specific tumor targeting and significantly increased tumor uptake after periodical treatment with InVNBL were evidenced by scintigraphic imaging, especially in mice bearing small tumors. CONCLUSION: The significant differences in the outcomes of cancer treatment and molecular imaging between animals bearing small and large tumors revealed that tumor burden is a critical and discriminative factor in cancer therapy using PEGylated liposomal drugs.

Therapeutic efficacy evaluation of 111In-labeled PEGylated liposomal vinorelbine in murine colon carcinoma with multimodalities of molecular imaging.

UNLABELLED: In our previous studies using combined radioisotopes with chemotherapeutic liposomal drugs (i.e., (111)In-labeled polyethylene glycol (PEG)ylated liposomal vinorelbine) we have reported possible therapeutic efficiency in tumor growth suppression. Nevertheless, the challenge remains as to whether this chemotherapy has a therapeutic effect as good as that of combination therapy. The goal of this study was to investigate the real therapeutic effectiveness of 6 mol% PEG (111)In-vinorelbine liposomes via the elevation of the radiation dosage and reduction in the concentration of chemotherapeutic agents. METHODS: Murine colon carcinoma cells transfected with dual-reporter genes (CT-26/tk-luc) were xenografted into BALB/c mice. The biodistribution was estimated to determine the drug profile and targeting efficiency of (111)In-vinorelbine liposomes. Bioluminescence imaging and (18)F-FDG small-animal PET were applied to monitor the therapeutic response after drug administration. The survival in vivo was estimated and linked with the toxicologic and histopathologic analyses to determine the preclinical safety and feasibility of the nanomedicine. RESULTS: Effective long-term circulation of radioactivity in the plasma was achieved by 6 mol% PEG (111)In-vinorelbine liposomes, and this dose showed significantly lower uptake in the reticuloendothelial system than that of 0.9 mol% PEG (111)In-vinorelbine liposomes. Selective tumor uptake was represented by cumulative deposition, and the maximum accumulation was at 48 h after injection. The combination therapy exhibited an additive effect for tumor growth suppression as tracked by caliper measurement, bioluminescence imaging, and small-animal PET. Furthermore, an improved survival rate and reduced tissue toxicity were closely correlated with the toxicologic and histopathologic results. CONCLUSION: The results demonstrated that the use of 6 mol% PEG (111)In-vinorelbine liposomes for passively targeted tumor therapy displayed an additive effect with combined therapy, not only by prolonging the circulation rate because of a reduction in the phagocytic effect of the reticuloendothelial system but also by enhancing tumor uptake. Thus, this preclinical study suggests that 6 mol% PEG (111)In-vinorelbine liposomes have the potential to increase the therapeutic index and reduce the toxicity of the passively nanotargeted chemoradiotherapies.

Evaluation of pharmacokinetics of 111In-labeled VNB-PEGylated liposomes after intraperitoneal and intravenous administration in a tumor/ascites mouse model.

Nanoliposomes are important drug carriers that can passively target tumor sites by the enhanced permeability and retention (EPR) effect in neoplasm lesions. This study evaluated the biodistribution and pharmacokinetics of 111In-labeled vinorelbine (VNB)-encapsulated PEGylated liposomes (IVNBPL) after intraperitoneal (i.p.) and intravenous (i.v.) administration in a C26/tk-luc colon carcinoma ascites mouse model. IVNBPL was prepared by labeling VNB-encapsulated PEGylated liposomes with 111In-oxine. BALB/c mice were i.p. inoculated with 2 x 10(5) C26/tk-luc cells in 500 muL of phosphate-buffered saline. Peritoneal tumor lesions were confirmed by 124I-FIAU/micro-PET (positron emission tomography) and bioluminescence imaging. Ascites production was examined by ultrasound imaging on day 10 after tumor cell inoculation. The pharmacokinetics and biodistribution studies of IVNBPL in a tumor/ascites mouse model were conducted. The labeling efficiency was more than 90%. The in vitro stability in human plasma at 37 degrees C for 72 hours was 83% +/- 3.5%. For i.p. administration, the areas under curves (AUCs) of ascites and tumor were 6.78- and 1.70-fold higher, whereas the AUCs of normal tissues were lower than those via the i.v. route. This study demonstrates that i.p. administration is a better approach than i.v. injection for IVNBPL, when applied to the treatment of i.p. malignant disease in a tumor/ascites mouse model.